A device under test such as a semiconductor device is subjected to an electric test (inspection) as to whether or not its internal circuit acts as defined in a specification. Such an electric test is conducted by using an electric connecting apparatus such as a probe card with a plurality of contacts disposed on the underside of an insulating base plate.
As one of such electric connecting apparatus, there is a vertical type one (e.g., Japanese Patent Appln. Public Disclosure No. 2002-202337) wherein a lower plate and an upper plate are disposed at an interval in the vertical direction interposing a middle plate therebetween, wherein a plurality of needle type probes are assembled into the lower, middle and upper plates so as to penetrate these plates in the vertical direction, and wherein the lower end (needle point) of each probe is pressed against an electrode of the device under test.
A vertical type apparatus, which is easier in assembling probes than a conventional general apparatus with needle type probes bent like an L-shape assembled into a base plate in a cantilever state, is less expensive and can increase the density of arrangement of probes, or needle points, and is suitable for an electric test of a high density device under test having many electrodes.
Also, such a vertical type apparatus has the middle plate displaced in the horizontal direction relative to the upper and lower plates to curve the probes beforehand in the same direction, thereby preventing adjoining probes from coming into contact.
Further, the vertical type apparatus disposes an auxiliary plate above the lower plate at a small interval and forms a projected portion at a position of each probe between the auxiliary plate and the lower plate, thereby preventing the probe from passing through the auxiliary plate and the lower plate.
In the foregoing conventional vertical apparatus, however, the diameter of each probe is so small as approximately fifty microns to 100 microns, so that, unless the diameters of the through holes of the auxiliary and lower plates for the probe to penetrate are made so small as approximately fifty microns to 100 microns, the tip of the probe moves largely within the through holes, which results in dislocation of relative positions of the needle point and the electrode of the device under test. Also, it is difficult to form with high accuracy a through hole having such a small diameter within which the probe tip would not move largely.